A problem of the known apparatus is formed by the screening of the detection means against scattered light, i.e. light which is not transmitted via the egg but which falls on the detection means directly or via reflection surfaces. For a proper operation of the candling apparatus it is important that the amount of scattered light falling on the detection means is minimized. For this purpose, in U.S. Pat. No. 2,987,182 the path along which the eggs are moved is at least partly screened by a lightproof tunnel, with a light source disposed on one side of the path and detection means disposed on the other side. Because of the presence of the tunnel, the detection means will receive only little scattered light. Nevertheless, the detection means continue to receive a particular amount of scattered light, so that this solution is not yet entirely satisfactory. Moreover, the solution is only practicable in a suitable manner if only one path of travel is present. When several parallel paths of travel are present, the space that will be occupied by the light source and the detection means will lead to a large distance in between the paths or to a great length of the path along which detection means are disposed.